Conventional Radio Frequency (RF), microwave, and millimeter wave power transmission systems transmit power within a given specified operating range. The operating range is typically regulated on a system level, where the output power is monitored, processed, and fed back for gain control.
Such conventional systems use a coupler to sample a fractional amount of transmitted high frequency power. The high frequency power is then fed into a detection circuit which is typically a diode rectification and charge storage circuit which extracts the RMS DC voltage equivalent of the high frequency signal. The DC signal is then fed into a signal control block that relates the detected voltage to a calibrated table that relates DC voltage to measured output power. The desired output power is compared to the actual power, and the resulting delta is stored. The signal control unit then calculates what control signal is needed for gain control to achieve the delta. The control signal is then sent to the gain control unit which then attenuates or amplifies the signal. The system repeats this cycle until the requested output power is achieved.
The accuracy and speed of such a power regulation system is highly dependent on the total error of the number of elements the control signal must pass through. There is also a relatively long time lag through all the system elements resulting in a slow control loop. Such a system is also rather large, implementing the coordination of many elements, voltage translations, and comparisons.
It would be desirable to implement a monolithic integrated power regulation utilizing power detection for bias control.